In a liquid crystal display apparatus, the display panel includes multiple pixels arranged in multiple matrix arrays. Each pixel includes several sub-pixels respectively for displaying different colors, such as red, green, and blue. The brightness of each sub-pixel in each pixel is determined by both an emitted light intensity from a backlight module of the liquid crystal display apparatus and a grayscale level of this sub-pixel. Different colors can be generated at different pixels through mixing the light from three sub-pixels respectively controlled at different brightness. In a conventional method of driving the liquid crystal display apparatus, the liquid crystal molecules associated with different sub-pixels in the display panel are rotated to different angles driven by different values of a grayscale voltage to achieve different grayscale levels in brightness for displaying different color and brightness for each pixel.
During an actual image display operation using the liquid crystal display apparatus, it is often occurred that the brightness of one colored sub-pixel of a pixel may be lowered for some reason. For example, in a display apparatus having a blue-light preventer, a thin-film filter absorbs blue light of certain wavelengths emitted from the display panel to make the brightness of blue sub-pixels lowered to a level below a theoretical level of assuming no blue-light preventer. Because of brightness reduction of a certain-colored sub-pixel in a pixel, a color shift problem will occur in the displayed image. For example, the display image of a display apparatus having blue-light preventer usually looks like yellowish. The color shift problem of the display apparatus reduces effective viewing quality of the display apparatus.